FJ Cruiser Head Unit INSTALLED in 1991 FJ80
So, I learned some very valuable info that I wish I had before my install. So I thought I would pass it on. First off the quoted post from photogod about taking out the factory amp is very important. Apparently a lot of head units with internal amps don't co operate well with the toyota factory amp so it has to go. The head unit I got from a 2007 FJ Cruiser was heating up outrageously until I bypassed the amp. Second off Toyota used the same wiring harness for the head unit for almost all of their vehicles from 1989 on. What this means is that most factory Toyota/Scion head units will literally plug right in and play(mine did). IMPORTANT: there are (3) plugs behind the head unit. Only one small one will be plugged into the stock Toyota head unit. The two plugs that are not being used are the ones that an aftermarket harness, or in my case the FJ Cruiser HU will plug into.
So, Here is what I did. And it was super easy, although a little time consuming.
1. I took out the glove box and took off the passenger side dash speaker cover right next to it. Under this cover you will see the speaker and two screws that hold the amp(which is mounted right behind the speaker by the way)
2. Remove the amp and note the three plugs that are plugged into it. One is small on one side by itself and wont be used and the other two are on the same side together and match the two behind the head unit that were not in use with the factory head unit.
3. Here is were you have a couple of options depending on what you are trying to accomplish. photogod's post says that he purchased the aftermarket wiring harness and plugged right into the two plugs coming out of the amp. Personally I chose to cut off the two plugs that went into the amp, cut off the two matching plugs behind the head unit leaving as much length as possible on them and wire them together with enough extra wire between them to make the plugs reach to the head unit. This is pretty easy since the wires are all color coded. You just get some wire, some crimp connectors and go to town.
So now you have two factory plugs behind the head unit without the troublesome factory amp in the way and you can either get a stock Toyota/Scion unit and plug right into it or buy a wiring harness(like Scosche) and put in an aftermarket HU of your choice.
Like I said this was super easy to do and works great. The most difficult part for me was trimming the plastic bezel to fit the FJ Cruiser HU.
It sounds pretty good with the factory speakers but the next step will be to upgrade them. I am also going to buy an Ipod adapter that plugs into the back of the head unit.